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Analog Devices Inc./Maxim Integrated MAX805LCPA+
- Part No.:
- MAX805LCPA+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- 8-DIP (0.300", 7.62mm)
- Datasheet:
-
MAX805LCPA+.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL 8DIP
- Quantity:
- Payment:
- Shipping:
Inventory:2,793
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Product details
Overview
MAX805LCPA+ from Maxim Integrated is a microprocessor supervisory circuit providing active-high reset, battery-backup switchover, watchdog timer, and power-fail detection in a single 8-pin PDIP package. It asserts RESET at 4.65V threshold with 200ms pulse width, supports VCC down to 1.1V for valid reset output, draws only 200µA supply current, and enables CMOS RAM retention during brownout. It is used in battery-powered controllers requiring reliable power monitoring and nonvolatile memory backup.
For engineers reviewing the MAX805LCPA+ datasheet, MAX805LCPA+ pinout, MAX805LCPA+ application, or MAX805LCPA+ equivalent, key selection criteria include its active-high RESET output (vs. active-low on MAX690A), guaranteed operation down to VCC = 1.1V, ±2% power-fail accuracy, 1.6s watchdog timeout, and compatibility with lithium backup batteries up to 4.80V.
Technical Context
The MAX805LCPA+ integrates four core functions: a precision 4.65V reset comparator with 40mV hysteresis, a 1.6s watchdog timer cleared by WDI edges or reset assertion, a 1.25V reference-based power-fail comparator (PFI/PFO), and bidirectional battery switchover logic that connects VBATT to VOUT only when VCC falls below 4.65V and VBATT exceeds VCC by ≥20mV.
Its active-high RESET output is the logical inverse of the MAX690A's RESET, enabling direct interface with µPs like the Intel 80C51 requiring high-true reset. The internal PMOS switch for VOUT has 5Ω on-resistance when powered from VCC and 80Ω when powered from VBATT, with quiescent current dropping to 50nA in full battery-backup mode.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 4.65V ±50mV - triggers reset during power-up, brownout, or power-down when VCC drops below this level |
| Reset Pulse Width | 200ms - ensures µP receives sufficient reset duration for reliable initialization |
| Watchdog Timeout | 1.6s - detects µP lockup if WDI is not toggled within this interval |
| Supply Current | 200µA typical - minimizes main supply loading during normal operation |
| Battery-Backup Current | 50nA - extends lithium battery life for multi-year RAM retention |
| Power-Fail Reference | 1.25V ±2% - enables accurate undervoltage detection for +5V or other rails via external divider |
| VCC Operating Range | 1.1V to 5.5V - guarantees RESET output validity even during deep brownout |
Pinout & Package
MAX805LCPA+ is housed in an 8-pin plastic DIP (PDIP) package with 0.300" wide body and 0.100" lead pitch. Pin 1 is marked with a dot or notch; pins are numbered counterclockwise from top-left when viewed from top.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - VOUT | CMOS RAM supply output | Switches between VCC (via 5Ω PMOS) and VBATT (via 80Ω PMOS) based on VCC/VBATT comparison relative to reset threshold |
| 2 - VCC | Main +5V supply input | Primary power source; powers internal circuitry and drives VOUT when above reset threshold |
| 3 - GND | Ground reference | Common return path for all analog and digital functions; must be low-impedance |
| 4 - PFI | Power-fail comparator input | Monitors divided-down supply voltage; asserts PFO low when input falls below 1.25V |
| 5 - PFO | Power-fail output | Open-drain active-low signal indicating supply undervoltage or low-battery condition |
| 6 - WDI | Watchdog timer input | Edge-sensitive input; reset triggered if held static >1.6s; floating or tri-stated disables watchdog |
| 7 - RESET | Active-high reset output | Push-pull output asserted high during reset; valid down to VCC = 1.1V; replaces MAX690A's active-low RESET |
| 8 - VBATT | Backup battery input | Supplies VOUT during VCC failure; accepts lithium cells up to 4.80V; enables <1µA standby draw when VCC < VBATT −1V |
Key Features
| Feature | Design Value |
|---|---|
| Active-high RESET output | Directly interfaces with Intel 80C51 and other µPs requiring high-true reset without external inversion |
| Guaranteed RESET assertion to VCC = 1.1V | Ensures deterministic reset behavior during severe brownout conditions where VCC collapses below 1.2V |
| ±2% power-fail accuracy | Enables precise early-warning detection of supply degradation before critical µP operation fails |
| 50nA battery-backup quiescent current | Supports >10-year lithium battery life for static RAM retention in unattended systems |
| VBATT switchover hysteresis | 40mV prevents oscillation during slow VCC ramp-down by requiring 20mV rise before reconnection to VCC |
Applications
| Industrial Data Loggers | Medical Patient Monitors |
|---|---|
Use Scenario: Long-term battery-operated devices recording sensor data with SRAM buffer during AC power loss. IC Role / Device Role / Timing Role: Supervisory IC providing active-high reset, seamless VBATT-to-VOUT switchover, and power-fail warning to trigger safe data save. Use Value: Prevents data corruption by ensuring µP reset and RAM retention during brownout, enabled by 50nA backup current and 4.65V threshold accuracy. |
Use Scenario: Portable diagnostic equipment requiring uninterrupted operation and fail-safe shutdown upon low battery. IC Role / Device Role / Timing Role: Power monitor generating RESET pulse and PFO alert when main supply or battery voltage degrades below safe thresholds. Use Value: Guarantees µP enters known state before power collapse, while PFO interrupt initiates controlled shutdown and data preservation. |
| Point-of-Sale Terminals | Smart Utility Meters |
Use Scenario: Transaction-critical terminals operating on mains with supercapacitor backup during brief outages. IC Role / Device Role / Timing Role: Supervisory controller asserting RESET and switching VOUT to backup source within 200ms of VCC drop below 4.65V. Use Value: Eliminates transaction loss by maintaining RAM state and forcing µP reset before corrupted execution begins. |
Use Scenario: Meters with nonvolatile memory needing tamper-proof timekeeping and firmware integrity across decades. IC Role / Device Role / Timing Role: System supervisor delivering 200ms RESET pulse, 1.6s watchdog timeout, and battery-backed VOUT for real-time clock and metering registers. Use Value: Ensures meter continues accurate timekeeping and retains billing data during grid instability, supported by 4.80V max VBATT rating. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX690ACPA+ | Provides active-low RESET output; identical 4.65V threshold, 200ms pulse, and 1.6s watchdog; same 8-pin PDIP package | Requires external inverter for µPs needing active-high reset; otherwise functionally interchangeable in reset timing and battery switchover | Select MAX690ACPA+ only if system design already accommodates active-low reset signaling and no µP interface changes are desired |
| MAX802LCPA+ | Shares identical pinout and 4.65V reset threshold but outputs active-low RESET; differs only in RESET polarity and minor quiescent current spec (200µA vs. 350µA max) | Not suitable for direct replacement where active-high reset is mandatory; requires PCB-level redesign or level-shifting | Choose MAX802LCPA+ only when legacy compatibility with MAX690A footprint and active-low reset is required |
Compared with MAX690ACPA+ and MAX802LCPA+, the MAX805LCPA+ uniquely delivers guaranteed active-high RESET down to VCC = 1.1V-enabling robust operation in deeper brownout scenarios where the alternatives may lose output drive strength or assert invalid logic levels.
Availability
MAX805LCPA+ is available at Aetrix Electronics and suitable for industrial data loggers, medical patient monitors, point-of-sale terminals, smart utility meters, and embedded controllers requiring stable component supply with long lifecycle support.
Supply support for MAX805LCPA+ includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
Maxim Integrated (now part of Analog Devices) designs precision analog, mixed-signal, and power management ICs for demanding industrial, medical, and communications applications.
The MAX805LCPA+ belongs to Maxim's microprocessor supervisory product line, engineered specifically to replace discrete reset generators and battery switches in µP-based systems while guaranteeing reliability under brownout, power-fail, and watchdog fault conditions.
FAQ
What is the reset threshold voltage of the MAX805LCPA+ and how tightly is it specified?
The MAX805LCPA+ has a nominal reset threshold of 4.65V, with a guaranteed range of 4.50V to 4.75V over temperature and supply variations. This specification ensures consistent power-on reset behavior and reliable brownout detection across industrial temperature ranges, directly supporting stable µP initialization in +5V systems.
How does the MAX805LCPA+ differ from the MAX690A in terms of reset output polarity and compatibility?
The MAX805LCPA+ provides an active-high RESET output, whereas the MAX690A provides active-low RESET. They share identical pinout, 4.65V threshold, 200ms pulse width, and battery switchover functionality. Because of the polarity difference, the MAX805LCPA+ cannot be substituted for the MAX690A without verifying µP reset input logic requirements - the MAX805LCPA+ is intended for µPs like the Intel 80C51 that require high-true reset.
What is the minimum VCC voltage at which the MAX805LCPA+ guarantees valid RESET output?
The MAX805LCPA+ guarantees valid active-high RESET output down to VCC = 1.1V, as confirmed in the Electrical Characteristics table under "RESET Output Voltage" for MAX805LC grade. This allows the device to maintain deterministic reset signaling during deep brownout events where VCC collapses below 1.2V - a capability not shared by many competing supervisory ICs.
Can the MAX805LCPA+ monitor power supplies other than +5V using the PFI input?
Yes - the MAX805LCPA+ features a dedicated 1.25V internal reference for the PFI comparator, allowing it to monitor any DC supply rail via an external resistor divider. For example, a +3.3V rail can be scaled to 1.25V at PFI using R1/R2 = 1.64, enabling precise undervoltage detection independent of the main VCC supply.
What is the maximum allowable backup battery voltage for the MAX805LCPA+ and why is this limit imposed?
The MAX805LCPA+ supports a maximum VBATT voltage of 4.80V, as specified in Table 2 of the datasheet. Exceeding this limit risks forward-biasing the internal substrate diode (D1 in Figure 3) when VCC is near the reset threshold, causing unintended current flow from VBATT into the VCC domain and potential functional disruption or increased leakage.
MAX805LCPA+ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 8-DIP (0.300", 7.62mm)
- Packaging:
- Tube
- Product Status:
- Active
- Programmable:
- Not Verified
- Type:
- Battery Backup Circuit
- Number of Voltages Monitored:
- 1
- Voltage - Threshold:
- 4.65V
- Output:
- Push-Pull, Totem Pole
- Reset:
- Active High
- Reset Timeout:
- 140ms Minimum
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 8-PDIP
MAX805LCPA+ FAQ
1.How can I place an order for MAX805LCPA+ through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX805LCPA+ on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for MAX805LCPA+ reliable?
The price and inventory of MAX805LCPA+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX805LCPA+ is usually 5 days.
3.What payment methods are accepted for MAX805LCPA+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX805LCPA+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX805LCPA+?
MAX805LCPA+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX805LCPA+ order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for MAX805LCPA+?
For technical support, including MAX805LCPA+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX805LCPA+ requirements.
6.How does Aetrix verify that MAX805LCPA+ is sourced from the original manufacturer or authorized distributors?
All MAX805LCPA+ products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that MAX805LCPA+ meets industry standards.
7.What is the process for return or replacement of MAX805LCPA+?
All MAX805LCPA+ units undergo pre-shipment inspection (PSI). If there is an issue with MAX805LCPA+, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The MAX805LCPA+ part is unused and in its original packaging.
Return procedure for MAX805LCPA+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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